Matt Thornton officially changed the color of his Sox on Saturday, as he joined the Red Sox in Oakland following Boston’s trade with the White Sox on Friday. The 36-year-old reliever is ready for the new challenges that come with such a wardrobe change.

“They’re a first-place team,” Thornton said while speaking to the media for the first time as a member of the Red Sox. “It’s all about winning in this game. That’s why I prepare in the offseason is to win ballgames. Unfortunately, in Chicago, we weren’t playing real good all year long and never found consistency over there. But I’m really excited to come over here and help out. I’ve been smiling pretty much all day, knowing that I’m going to be on a first-place team and in a pennant race down the stretch.”

Thornton is certainly going from one end of the spectrum to the other. The White Sox are in the basement of the AL Central, sitting at 37-54 and 13 games back of the first-place Tigers, and the Red Sox hold the American League’s best record at 58-38. So while Thornton may have enjoyed his eight seasons in Chicago, the change of scenery comes at a perfect time for the left-hander.

“I had a good relationship with everyone over there. But at the same time, I had heard about the rumors to Boston,” Thornton said. “The opportunity to come over [to Boston] was great for me.”

Thornton, who has a 3.86 ERA in 28 innings over 40 appearances this season, adds a left-handed option to the Red Sox’ bullpen, which is something they needed even more after Andrew Miller was placed on the 60-day disabled list with a foot injury. Thornton figures to be more of a matchup guy around the middle innings, but he said Saturday that he’s ready to provide “whatever they need from me.”

Only time will tell what kind of impact Thornton will have. He has a proven track record, even earning an All-Star selection in 2010, but he has shown some signs of regression. One thing that’s already clear, though, is that Thornton should have no trouble fitting in with the Red Sox’ tight-knit group.

“He’ll fit really well in this clubhouse,” said pitching coach Juan Nieves, who spent five years working with Thornton as Chicago’s bullpen coach before this season. “He’s a guy who’s dedicated to his work and he’s also very good against lefties. Matt has shown consistency and resiliency — absolutely he can pitch every day. He’s been through the grind before and has been in situations like this. We’re more than welcome to have him.”

Thornton said that he’s excited about his new situation. The Red Sox will be every bit as excited if he ends up becoming the valuable contributor they think he can be.